Water driven adsorption of amino acids on the (101) anatase TiO

Lorenzo Agosta, Giuseppe Zollo, Caterina Arcangeli, Francesco Buonocore, Fabrizio Gala, Massimo Celino

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Abstract

Arg, Lys and Asp amino acids are known to play a critical role in the adhesion of the RKLPDA engineered peptide on the (101) surface of the titania anatase phase. To understand their contribution to peptide adhesion, we have considered the relevant charge states due to protonation (Arg and Lys) or deprotonation (Asp) occurring in neutral water solution, and studied their adsorption on the (101) anatase TiO2surface by ab initio total energy calculations based on density functional theory. The adsorption configurations on the hydrated surface are compared to those on the dry surface considering also the presence of the hydration shell around amino acid side-chains. This study explains how water molecules mediate the adsorption of charged amino acids showing that protonated amino acids are chemically adsorbed much more strongly than de-protonated Asp. Moreover it is shown that the polar screening of the hydration shell reduces the adsorption energy of the protonated amino acids to a small extent, thus evidencing that both Arg and Lys strongly adhere on the (101) anatase TiO2surface in neutral water solution and that they play a major role in the adhesion of the RKLPDA peptide.
Original languageEnglish
Pages (from-to)1556 - 1561
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume17
Issue number3
DOIs
Publication statusPublished - 21 Jan 2015

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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